Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in PYTHON3):

Solution:
#815A

inpt = input().split(" ")
n = int(inpt[0])
m = int(inpt[1])

arr = []

for i in range(n):
	inpt = input().split(" ")
	inpt = list(map(int, inpt))
	arr.append(inpt)

sol = []

def solver1(a, sol):
	allmin = min([min(suba) for suba in a])
	if allmin < 0:
		return False
	allmax = max([max(suba) for suba in a])
	if allmax == 0:
		return True
	else:
		for i in range(len(a)):
			p = min(a[i])
			if p > 0:
				for j in range(len(a[i])):
					a[i][j] -= p
				for q in range(p):
					sol.append(i + 1)
				return solver1(a, sol)
		for j in range(len(a[0])):
			b = []
			for i in range(len(a)):
				b.append(a[i][j])
			p = min(b)
			if p > 0:
				for k in range(len(b)):
					a[k][j] -= p
				for q in range(p):
					sol.append(len(a) + j + 1)
				return solver1(a, sol)

def solver2(a, sol):
	allmin = min([min(suba) for suba in a])
	if allmin < 0:
		return False
	allmax = max([max(suba) for suba in a])
	if allmax == 0:
		return True
	else:
		for j in range(len(a[0])):
			b = []
			for i in range(len(a)):
				b.append(a[i][j])
			p = min(b)
			if p > 0:
				for k in range(len(b)):
					a[k][j] -= p
				for q in range(p):
					sol.append(len(a) + j + 1)
				return solver2(a, sol)
		for i in range(len(a)):
			p = min(a[i])
			if p > 0:
				for j in range(len(a[i])):
					a[i][j] -= p
				for q in range(p):
					sol.append(i + 1)
				return solver2(a, sol)

if n < m:
	if solver1(arr, sol):
		print(len(sol))
		for i in sol:
			if i <= n:
				print("row", i)
			else:
				print("col", i - n)
	else:
		print("-1")
else:
	if solver2(arr, sol):
		print(len(sol))
		for i in sol:
			if i <= n:
				print("row", i)
			else:
				print("col", i - n)
	else:
		print("-1")